Shell Programming and Scripting

I have a very large (150 megs) IRC log file from 2000-2001 which I want to cut down to individual daily log files. I have a very basic knowledge of the cat, sed and grep commands. The log file is time stamped and each day in the large log file begins with a "Session Start" string like so:

Session Start: Tue Mar 21 03:54:00 2000

Any idea how I could take this large log file, and use sed/grep to break it up in to individual daily versions? Ideally the output would save in to a directory of my chosing in sequential format. Something like so: "resultingfile001.log" and "resultingfile002.log" and so on. I will manually rename the files afterwards.

Any and all help would be greatly appreciated!

I would suggest using awk...

Code:

awk '
/Session Start:/ {
  close f
  ++n
}
{
  f=sprintf("resultingfile.%03d",n)
  print $0 > f
}
' largelogfile

split and dd will also do what you need.

Carriage-control files work the best with split. IMO.

How? Have you got an example? I didn't know that split or dd could search files for a particular pattern. My versions of split and dd can only break-up a file into fixed-size pieces.

My bad.

They are modified versions of dd and split. They accept '-exec ' like arguments -- it allows us to embed commands like 'grep -l' which return multiple line numbers.

We reformat huge numbers of files and convert between ASCII-EBCDIC, so a decision was made a long time ago to do it this way.

I appreciate everyone's follow-ups. I tried using this code, dumped it in to a shell script, chmod'ed it and tried running it. There seems to be a problem, however. It gave me one "resultingfile.001" but stopped afterwards. Any pointers? Otherwise it appears it will do exactly what I need it to!

Thank you very much for your help, Ygor!

Perhaps you using an old version of awk? On some systems the newer awk is called nawk.